A Galaxy is the largest type of military formation fielded by the Clans, equivalent to a Brigade in the defunct Star League Defense Force. It consists of several Clusters and is commanded by a Galaxy Commander. Galaxies are self-contained units which include all the necessary assets to mount independent operations, though in practice Galaxies rarely take to the field of battle as one unified force.[1]

Some Galaxies can have as few as two Clusters,[2][3] while others can have as many as six.[1] Most Galaxies though will have anywhere from three to five Clusters, with an average of four, and include an independent command Trinary or Cluster.[2][3][4]

Nicholas Kerensky himself recognized that Galaxies were more for logistical purposes than anything else and unlike smaller formations never set down criteria for their composition.[2][3] Support elements such as engineers, artillery and MASH units are organized at the Galaxy level but can be attached to individual Clusters as needed.[1]